The present invention relates to a heat-resisting fiber-reinforced composite material and manufacturing method thereof. More particularly, it relates to a heat-resisting fiber-reinforced composite material used for gas turbine combustors, moving and stationary blades, heat resisting panels for space shuttles, and heat shielding partition walls, and manufacturing method thereof.
Conventionally, there has been much attention paid to ceramic fiber-reinforced ceramics that is a kind of composite material as a material used for gas turbine combustors, moving and stationary blades, heat resisting panels for space shuttles, and heat shielding partition walls.
However, it is difficult to precisely fill a ceramic base material into ceramic fiber in the manufacturing process, and there exists a lot of internal defects in the ceramic fiber-reinforced ceramics obtained. Accordingly, when a gas turbine combustor or the like is manufactured by using such ceramic fiber-reinforced ceramics, the gas turbine combustor or the like thus manufactured is unable to assure the designed strength.
On the other hand, in the case of fiber-reinforced glass that is a kind of composite material, the glass used as a base material is relatively easier to soften and melt, and it is possible to precisely fill the glass into the fiber. Accordingly, the strength of fiber-reinforced glass using glass as a base material is excellent. And, in the case of a composite material using glass-based ceramic fiber, it is possible to make the composite material very high in strength since glass may be precisely filled into ceramic fiber. Accordingly, a gas turbine combustor or the like made up of such ceramic fiber-reinforced glass may assure a very high strength.
However, fiber-reinforced glass capable of maintaining a sufficient strength at temperatures exceeding 1,200 degree C. is not available yet because of heat resistance capability of the glass. Therefore, a gas turbine combustor or the like made up of such ceramic fiber-reinforced glass cannot be used for parts exposed to a temperature higher than 1,200 degree C.
In the meantime, even in the case of a part such as a gas turbine combustor or the like required to be heat-resistant, the entire part is not always uniformly exposed to high temperatures. For example, it is well known that, in a gas turbine combustor, the temperature of the portion exposed to the flames becomes a high temperature level of about 1,200xcx9c1,300 degree C. while the temperature of the portion where the combustor is fitted to the gas turbine body becomes a medium temperature level of about 700 degree C.
Also, it is known that such temperature difference generated in same part can cause generation of a thermal stress in accordance with the temperature difference. Further, the thermal stress is increased as the thermal expansion is restrained. It can be said with respect to a gas turbine combustor that the thermal stress becomes higher at the portion where the combustor is fitted to the gas turbine body. Accordingly, if the combustor is fitted to the gas turbine body simply by using bolts and nuts for example, the portion where the combustor is fitted to the gas turbine will be damaged due to the thermal stress in use. Therefore, it is necessary to lessen the thermal stress generated at the fitting portion. In a conventional method, a flexible structure using a spring or the like is employed to release the thermal stress generated at the portion where the combustor is fitted to the gas turbine body, which causes the structure to become complicated. Also, there is less freedom in design because the structure is complicated.
Further, when making a combustor wherein a region of ceramic fiber-reinforced ceramics being able to withstand high temperatures and a region of ceramic fiber-reinforced glass being unable to withstand high temperatures but high in strength are selectively formed, it is preferable to let the material transfer in a transition manner for the purpose of reducing the stress at the boundary between the both regions.
For example, at the boundary between the region of ceramic fiber-reinforced ceramics at the high temperature side and the region of ceramic fiber-reinforced glass at the low temperature side, it is preferable to use ceramic fiber-reinforced ceramics on the inside and ceramic fiber-reinforced glass on the outside while gradually reducing the thickness of ceramic fiber-reinforced ceramics layer towards the ceramic fiber-reinforced glass region on the low temperature side and, on the other hand, gradually increasing the thickness of ceramic fiber-reinforced glass layer towards the ceramic fiber-reinforced glass region. However, there is no such structure and method developed in the past.
The present invention has been made in order to solve the problems of such prior art, and an object of the invention is to provide a heat-resisting fiber-reinforced composite material being able to achieve a desired heat resistance and strength and to reduce generation of thermal stress, and manufacturing method thereof.
A heat-resisting fiber-reinforced composite material of the present invention is a heat-resisting fiber-reinforced composite material used for a product or a part that generates temperature distribution, characterized in that the thermal expansion coefficient at a portion corresponding to a medium to low temperature range is greater than the thermal expansion coefficient at a portion corresponding to a high temperature range and that the boundary between the portion corresponding to the medium to low temperature range and the portion corresponding to the high temperature range is a transition region.
A heat-resisting fiber-reinforced composite material of the present invention is specifically a heat-resisting fiber-reinforced composite material used for a product or a part that generates temperature distribution, characterized in that a portion corresponding to a medium to low temperature range is heat-resisting fiber-reinforced glass of which thermal expansion coefficient is greater than that of heat-resisting fiber-reinforced ceramics, a portion corresponding to a high temperature range is heat-resisting fiber-reinforced ceramics, and the boundary between the portion corresponding to the medium to low temperature range and the portion corresponding to the high temperature range is a transition region of heat-resisting fiber-reinforced glass and heat-resisting fiber-reinforced ceramics.
In a heat-resisting fiber-reinforced composite material of the present invention, the heat-resisting fiber is, for example, ceramic fiber.
On the other hand, a method of manufacturing a heat-resisting fiber-reinforced composite material of the present invention is a heat-resisting fiber-reinforced composite material used for a product or a part that generates temperature distribution, characterized in that a portion corresponding to a medium to low temperature range is heat-resisting fiber-reinforced glass of which thermal expansion coefficient is greater than that of heat-resisting fiber-reinforced ceramics, a portion corresponding to a high temperature range is heat-resisting fiber-reinforced ceramics, and the boundary between the portion corresponding to the medium to low temperature range and the portion corresponding to the high temperature range is a transition region of heat-resisting fiber-reinforced glass and heat-resisting fiber-reinforced ceramics, thereby pre-forming a molding in a desired shape through weaving, and the pre-formed molding is subjected to matrix forming treatment in order to obtain a heat-resisting fiber-reinforced composite material in the desired shape.
In a method of manufacturing a heat-resisting fiber-reinforced composite material of the present invention, weaving of ceramic fiber impregnated with glass powder at a specified ratio is for example performed.
Since a heat-resisting fiber-reinforced composite material is configured as described, it is possible to achieve necessary heat resistance and strength at the same time and also to reduce the thermal stress generated at the boundary between different materials. Accordingly, it is possible to improve the durability of parts manufactured by using the heat-resisting fiber-reinforced composite material.
On the other hand, a method of manufacturing a heat-resisting fiber-reinforced composite material of the present invention is configured as described, and it is possible to manufacture a heat-resisting fiber-reinforced composite material having aforementioned characteristics.
Also, a method of manufacturing a heat-resisting fiber-reinforced composite material of the present invention is able to control the mixing ratio of different materials in the transition region.